Quantum teleportation is a protocol that allows the transfer of an unknown quantum state from one location to another without physically moving the particle itself. This process relies on two key resources: quantum entanglement and classical communication.
How It Works:
- Entangled Pair: Two particles (say, A and B) are entangled and shared between two parties — Alice (sender) and Bob (receiver).
- Measurement: Alice performs a joint quantum measurement (Bell-state measurement) on her particle A and the unknown quantum state she wants to send.
- Classical Communication: Alice sends the result of her measurement to Bob via classical means (e.g., a phone or internet).
- Reconstruction: Bob uses this classical information to apply a specific quantum operation on his particle B, transforming it into an exact replica of the original state.
Key Points:
- The original quantum state is destroyed in the process, preserving the no-cloning theorem.
- Only quantum information is transmitted — not energy or matter.
- The process is instantaneous on the quantum level, but requires classical communication, so no faster-than-light signaling occurs.
Applications:
- Fundamental to quantum communication networks.
- A building block for quantum repeaters and quantum internet.
- Important in distributed quantum computing.
Quantum teleportation showcases the power of entanglement and lies at the heart of many future quantum technologies.